Device for rectifying alternating current



March 15, 1938. C, HAMBUECHEN 2,111,047

DEVICE FOR RECTIFYINGALTERNATING CURRENT Filed Aug. 4, 1935 I N VEN TOR. Om HHMBz/Ec/ff/v ATTORNEY.

Patented Mar. 15, 19

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neon non rutger WING: ALTEA'EHNG URREN'E Appiication August d,

l@ @Balm My present invention relates primarily to rectiers of the type Adescribed and claimed in my Patent No. 1,912,636 of June 6, 1933, and which employ rectifying couples or cells, eachconsisting of a copper sulde element, and an element of magnesium, or other electropositive metal. In the above mentioned patent there is described a method of producing a rectifying and bonding material between the elements or electrodes, which consists in moistening the contacting surfaces of the elements to initiate electro-chemical action, the products of which, when property dried and processed, bond'the elements together. The rectifying material formed according to this method produces an integral junction between the electrode elements, Which'is shown bythe fact that when the elements are pulled apart, surface portions of the magnesium adhere as a plating to the copper sulfide element. However,

in many instances the copper sulfide element is not completely plated, there remaining spots or areas on such element to which the magnesium has not adhered, indicating that there has not been a complete and uniform rectifying junction L' formed between the elements.

It is highly desirable tohave a complete 'and-uniform. rectifying junction for the electrode elements in order to reduce the internal resistance and increase the efficiency and life of the couple.

Iiv have discovered that when employing the so-called Wet process for forming the .rectifying couples, a greatly improved product is obtained by utilizing, instead of an electropositive element -of ypure magnesium, as described in -my patent above referred to, an element of an electropositive metal, preferably magnesium, which contains a small percentage of manganese. The manganese aids 'in vthe production of an improved rectifying junction. f

Another, and presently preferred method of constructing rectifying couples is 'to weld together a. copper sulfide element and a metal element, preferably v of magnesium orv magnesium-manganese alloy, between which elements is disposed, prior to the Welding operation, a relatively thin, highly rsistant lm of precipitated manganese. Such manganese coating is preferable formed in the following manner.

One side of la sheet of metal from which the electropositivd elements are to be produced is rubbed down -or polished with dry powdered pumice to remove any grease or oxide film,l the surface on the reverse side ojf the sheet remaining untreated. The sheet is then immersed in a solution containing a manganese salt, for exami933, Serial No. 683,713

(Cl. N35-365) ple manganese chloride, whereupon a relatively thin black coating of manganese is precipitated instantaneous1y,` upon the rubbed surface. Practically no manganese is precipitated on the unrubbed or untreated surface. The sheetis removed from the solution, dried, and washers are punched therefrom. It will thus appear that the electropositive electrode elements embodies a 'metal body, 'preferably of magnesium or magnesium-manganese alloy having a thinfilm of 10 precipitated manganese disposed on one side sur-iface. The precipitated manganese lm yis a very poor conductor of electricity, andin fact may be classed as an insulator.

The copper sulde elements may be conveniently produced by subjecting heated copper washersto the action of sulfur vapors un'til sulriding of the Washers is completed.

In forming up the couple, the copper sulfide element is pressed against the manganese lm of the electropositive element with pressure sufcient to cause the copper sulfide to permeate, or substantially iiow through the pores, or inter` stices of the precipitated manganese film'. While so compressed, current is pased through the couple in a sci-called buckingdirection, i. e., from the `metal to theA copper sulfide element, which is opposite to the direction of current flow when the couple is 4functioning as a irectiflen The adjacent surface portions of the elements become fused, due to the intense heat produced at the highly resistant manganese nlm, and rem i act, probably electro-thermically, toform a rectif fying material of slag-like appearance, which welds the elements together. lThe reason for passing the current through' the elements in a bucking or inverse direction is ,that fusing tem'- peratures are rapidly produced, Aandthe heat is substantially localized at the contacting surfaces of the elements Where fusion is desired.

The accompanying drawing illustrates a rectifying couple constructed in accordancel with the teachings of the present invention. Fig. 1 is a plan View of the couple, the individual elements thereof being in the shape of circular washers. Fig. 2 is a transverse sectional view taken at line 2--2 of Fig. 1. In the drawing, reference numeral l designates the electro-negativeelectrode element of copper-sulfide which is welded in the manner described to the manganese coated surface 2 of the electrofposltive electrode element of magnesium or magnesium-manganese alloy.

- I claim: v

1. In an electrical rectier, a rectifying couple comprising a copper sulfide element, a mag-v nesium-manganese alloy element, and a layerof precipitated manganese between said elements.

2. A rectifying couple comprising a copper sulde element and a magnesium element having a preformed coating of precipitated manganese in contact with the copper sulde element;

3. The process of making rectifying couples for current `rectiflers which includes precipitating a layer f manganese on a magnesium body, placing a copper sulfide body in contact with the said layer and pressing the bodies together with suiicient force to cause the copper sulde to impregnate the said layer.

4. The process of making electropositive electrode elements for current rectifiers which consists in treating a'surface of a magnesium sheet to remove therefrom any oxide film, and in immersing said sheet in a solution containing a manganese salt to cause a film of manganese to form on said treated surface.

5. The method of making current rectiers wlich consists in electrochemically depositing manganese on a surface of a magnesium or magnesium alloy element, placing a copper sulfide element in contacting adjacence with the said manganese, and in passing sufficient current through' said elements to form a welded junction therebetween.

6. The method of making -electrical rectiers which consists in forminga manganese coating or film on one surface of a magnesium element, placing. a, copper sulde element in contacting adjacence with the coated surface of said magnesium element, and passing current vthrough said elements to form a rectifying and bonding slag therebetween.

7. The method of making electrical rectiers which consists in forming, by precipitation, a manganese coating or lrnl on only one side surface of a magnesium element, in disposing the.

coated surface of said element in contacting adjacence with a copper sulfide element, in pressing Asaid elements together to cause the copper sulde to permeate the magnesium layer, and in passing current from said magnesium to said copper sulfide element to Weld said elements'together.

8. The process of making a dry surface contact rectifier which comprises the steps of producing a metallic manganese coating on a surl face of a relatively light electropositive metal, contacting such coating with a dense mass of a current conducting compound of the oxygen family of the sixth periodic group having electronegative characteristics, and passing a forming current through the elements so join'ed.

v 9. The process of making a dry surface contact rectifier which comprises the steps of producing a metallic manganese coating on one face of an aluminum element, establishing an electrical contact of a body of cuprous sulphide with said manganese coating, and passing a forming current through the members thus assembled to produce aconyersion of the metallic manganese im to atcompound thereof having asymmetric current conducting characteristics.

10. The process of making a dry surface contact rectier which comprises the steps of producing a metallic manganese coating on one-face of an laluminum element, establishing an eleclm to a compound thereof which is intimately united with said plate and forms therewith an asymmetric current conducting couple.

` CARL HAMBUECHEN. 

